The present invention relates to a method for development of silver halide photographic light-sensitive materials and particularly, to a photographic light-sensitive material which can provide a very high contrast negative image, a high sensitivity negative image and a good dot image quality.
To add hydrazine compounds to a silver halide photographic emulsion or a developer has been known, for example, in U.S. Pat. Nos. 3,730,727 (a developer comprising combination of ascorbic acid and hydrazine), U.S. Pat. No. 3,227,552 (use of hydrazine as an auxiliary developer for obtaining directly a positive color image), U.S. Pat. No. 3,386,831 (addition of .beta.-monophenylhydrazide of aliphatic carboxylic acids as a stabilizer for silver halide light-sensitive materials), and U.S. Pat. No. 2,419,975, and Mees. "The Theory of Photographic Process", the third edition (1966), page 281.
Among them, especially U.S. Pat. No. 2,419,975 discloses formation of high contrast negative images by addition of hydrazine compounds. That is, it discloses that when a hydrazine compound is added to silver chlorobromide emulsion and development is carried out with a developer of higher pH of 12.8, very high contrast photographic characteristics of more than 10 in gamma value (.gamma.) can be obtained. However, highly alkaline developers having a pH value close to 13 are susceptible to oxidation with air and unstable and cannot stand long-term storage or use. The super-high contrast photographic characteristics of more than 10 in gamma value are very useful for photographic reproduction of continuous tone images by means of dot images useful for printing plate making or for reproduction of line images
For such purpose, hitherto, a silver chlorobromide emulsion containing more than 50 mol%, preferably more than 75 mol% of silver chloride has been used and development has been conducted with a hydroquinone developer having very low effective concentration (normally 0.1 mol/l or less) of sulfite ion (lith development). However, according to this method, since concentration of sulfite ion in the developer is low, the developer is extremely unstable and cannot be stored for more than 3 days. Besides, all of the above methods must use silver chlorobromide emulsions of relatively high silver chloride content and thus, high sensitivity has not been able to be obtained. Therefore, it has been earnestly desired to obtain super-high contrast photographic characteristics useful for reproduction of dot images or line images by using emulsions of high sensitivity and stable developers.
U.S. Pat. Nos. 4,168,977, 4,224,401, 4,243,739, 4,269,929, 4,272,614, and 4,323,643 disclose silver halide photographic light-sensitive materials which give very high contrast negative photographic characteristics using stable developers, but it has come to be known that acylhydrazine compounds used therein have some defects. That is, these hydrazines have been known to generate nitrogen gas during development and this gas is collected in the film to form bubbles, which may damage photographic images. Therefore, there have been demanded such compounds as giving very high contrast photographic characteristics even with small addition amount for diminishing generation of the bubbles and besides reduction of production cost for light-sensitive materials. Moreover, if development is continued using these hydrazines, innumerable circular fogs (pepper fogs) often occur in unexposed portions to seriously damage the image quality.
Moreover, the conventional hydrazines are required in a large amount for sensitization and enhancement of contrast and when especially high sensitivity of light-sensitive materials is desired, the hydrazines are preferably used in combination with other sensitizing techniques (for example, to carry out strong chemical sensitization; to increase grain size; and to add the compounds which accelerate sensitization as disclosed in U.S. Pat. Nos. 4,272,606 and 4,241,164). However, employment of these sensitizing techniques in combination with the hydrazines, sometimes sensitization with time and increase of fog occur during storage. Furthermore, when development is conducted using the conventional hydrazines, so-called uneven development caused by uneven agitation of developer is liable to occur. This uneven development conspicuously occurs in development by automatic processor and when development is strengthened in order to avoid this phenomenon, there occurs the above-mentioned pepper fogging. Therefore, the compounds have been demanded which are free from the problem in stability with time, uneven development and pepper fog, are effective with addition of them in a small amount, and besides are easy in synthesis.